Brachytherapy is a type of radiation therapy that has proven efficacy for treating a variety of types of cancers, such as cervical cancer. In brachytherapy procedures, radiation is delivered to cancerous regions by positioning a radiation source in close proximity to a tumor, typically by using a physical applicator equipped with a radiation source. Brachytherapy procedures may offer advantages over external beam radiation therapies by enabling improved targeting of cancerous cells, thus reducing the likelihood that healthy cells are radiated during treatment.
Development of a conformal dose plan for cervical cancer patients receiving brachytherapy is typically guided by images obtained via one or more imaging modalities. For example, in some instances, two-dimensional (2D) X-ray imaging may be chosen for treatment planning due to its low cost and minimal impact on the workflow. However, since the information available through 2D X-ray imaging is inherently limited due to its 2D nature (e.g., it may be possible to visualize the applicator but not the patient's anatomy), many dose plans are based on one or more types of three-dimensional (3D) imaging modalities. For instance, magnetic resonance imaging (MRI) and computed tomography (CT) may be used to gain a greater depth of information than would be acquired with 2D X-ray imaging.
However, image-guided 3D conformal dose planning with MRI and/or CT introduces significant monetary costs, accessibility difficulties, and lengthened procedure times. For example, the imaging department in a hospital is typically located in a different area than the treatment department, thus requiring time and expenses associated with patient transport and facilities planning. In an attempt to overcome these difficulties, trans-abdominal ultrasound (TAUS) and trans-rectal ultrasound (TRUS) modalities have been developed. Unfortunately, TAUS does not enable visualization of the anatomy of interest since the rectum, bowel, applicator, and needles may not be visible in the acquired images. Similarly, TRUS may not enable visualization of the bladder, bowel, and applicator. Further, combining TAUS and TRUS presents alignment and calibration difficulties, in addition to introducing undesirable workflow complexity in the operating room. Additionally, air present in the field of view complicates the use of ultrasonic modalities.
Accordingly, there exists a need for improved imaging systems that enable image-guided brachytherapy treatment of cervical cancer while addressing one or more of these drawbacks.